libc/src/string/memmove.cpp

   1 //===-- Implementation of memmove -----------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/string/memmove.h"
  10 #include "src/__support/macros/config.h"
  11 #include "src/string/memory_utils/inline_memcpy.h"
  12 #include "src/string/memory_utils/inline_memmove.h"
  13 #include <stddef.h> // size_t
  14
  15 namespace LIBC_NAMESPACE_DECL {
  16
  17 LLVM_LIBC_FUNCTION(void *, memmove,
  18                    (void *dst, const void *src, size_t count)) {
  19   // Memmove may handle some small sizes as efficiently as inline_memcpy.
  20   // For these sizes we may not do is_disjoint check.
  21   // This both avoids additional code for the most frequent smaller sizes
  22   // and removes code bloat (we don't need the memcpy logic for small sizes).
  23   if (inline_memmove_small_size(dst, src, count))
  24     return dst;
  25   if (is_disjoint(dst, src, count))
  26     inline_memcpy(dst, src, count);
  27   else
  28     inline_memmove_follow_up(dst, src, count);
  29   return dst;
  30 }
  31
  32 } // namespace LIBC_NAMESPACE_DECL